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United States Patent |
6,092,487
|
Niki
,   et al.
|
July 25, 2000
|
Air supply/exhaust device for experimental animal rearing apparatus
Abstract
An air supply/exhaust device to be joined to a box-shaped rearing cage
included in an experimental animal rearing apparatus to supply or exhaust
air into or from the rearing cage. The air supply/exhaust device comprises
an air supply pipe having a front end section provided with air
supply/exhaust holes, and a stop ring mounted on a section of the air
supply pipe behind the front end section provided with the air
supply/exhaust holes. An elastic plug is mounted on a section of the air
supply pipe extending behind the stop ring so as to be in contact with a
back surface of the stop ring. The elastic plug has the shape of a
truncated cone tapered toward an extremity of the air supply/exhaust pipe,
and a spring holder is provided on the air supply pipe, and an elastic
pressing member is mounted on a section of the air supply pipe between the
elastic plug and the spring holder to press the elastic plug continuously
toward the stop ring. When the air supply/exhaust device is connected to a
box-shaped rearing cage, the elastic plug is inserted through an opening
formed in the rear end wall of an upper cage included in a box-shaped
rearing box into the upper cage and engages firmly with the edge of the
opening to seal the box-shaped rearing cage.
Inventors:
|
Niki; Motohiro (Bunkyo-ku, JP);
Kidachi; Atsushi (Sakura, JP);
Niki; Mieko (Bunkyo-ku, JP);
Niki; Etuko (Bunkyo-ku, JP);
Kidachi; Misako (Sakura, JP)
|
Appl. No.:
|
173792 |
Filed:
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October 16, 1998 |
Current U.S. Class: |
119/420; 119/493; 119/500 |
Intern'l Class: |
A01K 001/00 |
Field of Search: |
119/420,452,493,500,453
|
References Cited
U.S. Patent Documents
5165362 | Nov., 1992 | Sheaffer et al. | 119/452.
|
5865144 | Feb., 1999 | Semenuk | 119/456.
|
Foreign Patent Documents |
1056898 | Mar., 1998 | JP.
| |
10178950 | Jul., 1998 | JP.
| |
Primary Examiner: Poon; Peter M.
Assistant Examiner: Abbott; Yvonne R.
Attorney, Agent or Firm: Ladas & Parry
Claims
What is claimed is:
1. An air supply/exhaust device joined to a box-shaped rearing cage
included in an experimental animal rearing apparatus to supply/exhaust air
into/from the box-shaped rearing cage, said air supply/exhaust device
comprising:
an air supply pipe having a front end section provided with air
supply/exhaust holes;
stop means provided on a section of the air supply pipe behind the front
end section provided with the air supply/exhaust holes;
an elastic plug mounted on a section of the air supply pipe extending
behind a stop ring so as to be in contact with a back surface of the stop
ring, and having the shape of a truncated cone tapered toward an extremity
of the air supply/exhaust pipe;
a spring holder provided on the air supply pipe; and
an elastic pressing member mounted on a section of the air supply pipe
between the elastic plug and the spring holder to press the elastic plug
continuously toward the stop ring.
2. The air supply/exhaust device according to claim 1, wherein the
box-shaped rearing cage has an upper cage having a rear end wall provided
with an opening, a lower cage and a partition member capable of passing
air and interposed between the upper and the lower cage, and the air
supply pipe is inserted through the opening formed in the rear end wall of
the upper cage so that the elastic plug is pressed firmly to the edge of
the opening of the rear end wall of the upper cage so as to seal the
box-shaped rearing cage.
3. The air supply/exhaust device according to claim 1, wherein said air
supply/exhaust holes are provided in an upper portion of the said front
end section.
4. The air supply/exhaust device according to claim 1, wherein said stop
ring is adjustably screw-engaged with said air supply pipe.
5. The air supply/exhaust device according to claim 1, wherein said elastic
plug has an axial bore through which said air supply pipe extends.
6. The air supply/exhaust device according to claim 1, wherein said elastic
pressing member is a coil spring.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an air supply/exhaust device for an
experimental animal rearing apparatus for rearing experimental animals,
such as mice or rats and, more particularly, to an air supply/exhaust
device capable of supplying fresh air into a box-shaped rearing cage or of
exhausting air from the box-shaped rearing cage.
2. Description of the Related Art
Referring to FIGS. 5 to 7, a conventional experimental animal rearing
apparatus (hereinafter referred to simply as rearing apparatus) comprises
a rearing rack 2, a box-shaped rearing cages 3, air supply devices 4,
automatic water supply devices 5 and, if necessary, air exhaust devices.
As shown in FIG. 5, the rearing rack 2 is a vertical frame formed in the
shape of a rectangular parallelepiped by assembling angle irons or the
like, and having a back frame 6, a top frame and a bottom frame. The
bottom frame is supported on four casters 7. Formed between the top and
the bottom frame are, for example, three rearing cage storing spaces 8.
Each rearing cage storing space 8 is capable of storing, for example,
three box-shaped rearing cages 3 in a transverse arrangement.
As shown in FIG. 6, each box-shaped rearing cage 3 is made, for example, of
a transparent plastic material and is provided with a flange 9 around an
open upper end thereof. The open upper end of the box-shaped rearing cage
3 is covered with a lid 10. A rear end wall of the box-shaped rearing cage
3, i.e., an end wall to be in the back of the case storing space 8 when
the box-shaped rearing cage 3 is stored in the case storing space 8, is
provided with an opening 11 for receiving the air supply device 4, an
opening 12 for receiving the automatic water supply device 5 and, if
necessary, an opening, not shown, for receiving an air exhaust device.
As shown in FIGS. 6 and 7, the air supply device 4 has an air supply pipe
13 and a sealing cup 14. The air supply pipe 13 is provided in its upper
part with, for example, four air supply holes 15 to blow air upward. The
extremity of the air supply pipe 13 is closed with a pipe plug 16. The
sealing cup 14 is fitted on the air supply pipe 13 so as to be set in
contact with the outer surface of the rear end wall of the box-shaped
rearing cage 3 when the rearing cage 3 is put in place in the case storing
space 8. The air supply pipe 13 is attached to the back frame 6 so as to
project into the case storing space 8 and is connected to an air blower,
not shown. As shown in FIG. 7, the sealing cup 14 is formed in the shape
of a cup having a diameter greater than that of the opening 11 of the
box-shaped rearing cage 3 and provided with a flange 17 at its open end.
The sealing cup 14 is fitted on the air supply pipe 13 so as to open
toward the extremity of the air supply pipe 13.
Referring to FIG. 6, the automatic water supply device 5 has an outer pipe
18, a water supply pipe 19, and a sealing cup 20 similar to the sealing
cup 14 of the air supply device 4. The outer pipe 18 is attached to the
back frame 6 so as to project into the case storing space 8 and is
connected to a main water supply pipe 21. The sealing cup 20 is fitted on
the outer pipe 18 so as to open toward the extremity of the outer pipe 18.
If necessary, an air exhaust pipe of the same construction as the air
supply pipe 13 may be held on the back frame 6.
When the box-shaped rearing cage 3 is pushed into the case storing space 8,
the air supply pipe 13 of the air supply device 4 and the outer pipe 18 of
the automatic water supply device 5 are inserted through the openings 11
and 12, respectively, into the box-shaped rearing cage 3, and the
respective flanges 17 and 22 of the sealing cups 14 and 20 are brought
into close contact with the outer surface of the rear end wall of the
box-shaped rearing cage 3. Consequently, the box-shaped rearing cage 3 is
sealed and the air supply device 4 and the automatic water supply device 5
are joined firmly to the rear end wall of the rearing cage 3. Thus, fresh
air and fresh water can always be supplied to animals, such as mice or
rats, kept in the rearing cage 3. An air exhaust device can be joined to
the rearing cage 3 in the same manner.
The sealing cup 14 of the air supply device 4 needs the flange 17 of a
predetermined diameter to set the sealing cup 14 in close contact with the
surface of the rear end wall of the rearing cage 3. The sealing cup 14
cannot be set in close contact with the outer surface of the rear end wall
of the box-shaped rearing cage 3 unless the end surface of the flange 17
and the outer surface of the rear end wall of the rearing cage 3 are
clean, smooth and flat. The same condition applies to the automatic water
supply device 5. The sealing cups 14 and 20 have a large diameter and take
a large space. The sealing cup 14 is unable to seal the interior of the
rearing cage 3 properly and a gap may be formed between the end surface of
the flange 17 and the outer surface of the rear end wall of the rearing
cage 3 unless the sealing cup 14 is held on the air supply pipe 13 so that
a plane including the end surface of the flange 17 is substantially
perpendicular to the axis of the air supply pipe 13. The same condition
applies to the sealing cup 20 of the automatic water supply device 5.
Making the sealing cups 14 and 20 by molding rubber needs a mold having a
spherical surface, which is not easy to make and increases the cost of the
air supply device 4 and the automatic water supply device 5.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an air supply/exhaust
device for an experimental animal rearing apparatus, having a simple
construction, employing a plug of a relatively small outside diameter, and
capable of easily and surely sealing a box-shaped rearing cage.
According to the present invention, an air supply/exhaust device comprises:
an air supply pipe having a front end section provided with air
supply/exhaust holes; stop means provided on a section of the air supply
pipe behind the front end section provided with the air supply/exhaust
holes; an elastic plug mounted on a section of the air supply pipe
extending behind the stop ring so as to be in contact with a back surface
of the stop ring, and having the shape of a truncated cone tapered toward
an extremity of the air supply/exhaust pipe; a spring holder provided on
the air supply pipe; and an elastic pressing member mounted on a section
of the air supply pipe between the elastic plug and the spring holder to
press the elastic plug continuously toward the stop ring.
Preferably, the air supply pipe is inserted in a box-shaped rearing cage
having an upper cage, a lower cage and a partition member capable of
passing air and interposed between the upper and the lower cage through an
opening formed in a rear end wall of the upper cage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partly sectional side view of a box-shaped rearing cage
provided with an air supply/exhaust device in a preferred embodiment
according to the present invention, and an automatic water supply device;
FIG. 2 is an enlarged longitudinal sectional view of the air supply/exhaust
device shown in FIG. 1;
FIG. 3 is a perspective view of an elastic plug included in the air
supply/exhaust device shown in FIG. 1;
FIG. 4 is a perspective view of a grating serving as a partition member and
included in the box-shaped rearing cage shown in FIG. 1;
FIG. 5 is a perspective view of an experimental animal rearing apparatus;
FIG. 6 is a partly sectional side view of a box-shaped rearing cage
provided with a conventional air supply/exhaust device; and
FIG. 7 is a longitudinal sectional view of the air supply device shown in
FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 to 4, an air supply/exhaust device 31 in a preferred
embodiment according to the present invention is intended for use in
combination with an experimental animal rearing apparatus for rearing
experimental animals, such as mice or rats. A box-shaped rearing cage 25
includes an upper cage 26 made of a transparent plastic material and a
lower cage 27 made of a transparent plastic material. A grating 28, i.e.,
a partition member, formed by processing metal wires and capable of
passing air is placed in a step formed in the upper end of the lower cage
27. A rear end wall, i.e., an end wall of a rear part to be placed in the
back of the rearing cage storing space 8 (FIG. 5), of the lower cage 27 is
provided with an opening 29 for receiving an automatic water supply device
5. A feed box may be formed integrally with the grating 28 so as to be
suspended from the grating 28. The upper cage 26 has an open lower end.
The upper end of the lower cage 27 is nested in the lower end of the upper
cage 26. The rear end wall of the upper cage 26 to be inserted in the
rearing cage storing space 8 is provided with an opening 30 for receiving
the air supply/exhaust device 31.
As most clearly shown in FIG. 2, the air supply/exhaust device 31 comprises
a straight, elongate air supply pipe 32, a stop ring 33 provided with an
internal screw thread 39, an elastic plug 34, a compression coil spring 35
and a spring holder 46. The air supply pipe 32 is provided in its upper
part with, for example, four air supply holes 36 to blow air upward. The
open extremity of the air supply pipe 32 is closed with a pipe plug 37.
The stop ring 33 is screwed on a threaded section provided with an
external screw thread 38 of the air supply pipe 32. The air supply holes
36 need not necessarily open upward. The elastic plug 34 having the shape
of a truncated cone as shown in FIG. 3 is mounted on a section of the air
supply pipe 32 extending behind the stop ring 33 so as to be in contact
with the back surface of the stop ring 33 and to taper toward the
extremity of the air supply pipe 32. The elastic plug 34 is made of an
elastic material, such as rubber or a plastic material. The elastic plug
34 has an axial bore 40 through which the air supply pipe 32 is extended.
The air supply pipe 32 is provided with a flange 42 at its back end. The
flange 42 is joined to a flange 43 formed on a main air supply pipe 41
with a packing 44 sandwiched between the flanges 42 and 43 with bolts 45
and nuts screwed on the bolts 45. The coil spring 35 is compressed between
the elastic plug 34 and the spring holder 46 fixed to the air supply pipe
46 so that the elastic plug 34 is continuously pressed toward the stop
ring 33. The position of the spring holder 46 on the air supply pipe 32
may be axially adjustable.
When the box-shaped rearing cage 25 is inserted in a rearing cage storing
space 8 of a rearing rack 2 similar to that shown in FIG. 5, the air
supply pipe 32 is inserted through the opening 30 into the upper cage 26,
and then the elastic plug 34 is fitted into the opening 30. Since the
elastic plug 34 is continuously pressed toward the stop ring 33 by the
resilience of the coil spring 35, a peripheral part of a diameter
corresponding to that of the opening 30 of the elastic plug 34 is engaged
closely with the edge of the opening 30 of the upper cage 26. When the
box-shaped rearing cage 25 is pulled out of the rearing cage storing space
8, the axial movement of the elastic plug 34 on the air supply pipe 32
together with the box-shaped rearing cage 25 is limited by the stop ring
33. Therefore it does not occur that the elastic plug 34 is unseparably
caught in the opening 30 or the elastic plug 34 is removed from the air
supply pipe 32. The elastic plug 34 may be coated with grease to ensure
further reliable sealing of the box-shaped rearing cage 25 and to enable
the elastic plug 34 to be easily separated from the box-shaped rearing
cage 25 when the box-shaped rearing cage 25 is pulled out of the rearing
cage storing space 8.
Experimental animals, such as mice or rats, in the lower cage 27 are unable
to move from the lower cage 27 to the upper cage 26 because the upper cage
26 and the lower cage 27 are separated by the grating 28. Accordingly, the
grating 28 prevents the experimental animals in the lower cage 27 from
gnawing the elastic plug 34 of the air supply/exhaust device 31 connected
to the upper case 26.
Although the present invention has been described as applied to the air
supply/exhaust device 31 only for supplying air through the air supply
holes 36 into the box-shaped rearing cage 25, the term, Oair
supply/exhaust deviceO used herein shall signify an air supply device
capable of only supplying air, an air exhaust device capable of only
exhausting air or an air supply/exhaust device capable of both supplying
and exhausting air.
As is apparent from the foregoing description, the elastic plug having the
shape of a truncated cone can surely and easily be fitted in the opening
of the upper cage for the reliable sealing of the box-shaped rearing cage.
Since the outside diameter of the elastic plug is relatively small, a
plurality of air supply/exhaust devices similar to the air supply/exhaust
device described herein can be connected to a relatively small box-shaped
rearing cage. The air supply/exhaust device provided with the elastic plug
having a simple shape is inexpensive.
Although the invention has been described in its preferred form with a
certain degree of particularity, obviously many changes and variations are
possible therein. It is therefore to be understood that the present
invention may be practiced otherwise than as specifically described herein
without departing from the scope and spirit thereof.
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